1. Field of the Invention
The present invention relates to electronic circuit boards and to methods of making electronic circuit boards.
2. Background Information
Existing Printed Circuit Boards (PCBs) comprise a sheet of non-conductive material, typically fiberglass reinforced polymer, laminated with a conductive layer of copper. The copper can be laminated on both the top and bottom surfaces of the polymer sheet. Portions of the copper are removed by printing and etching to leave conductive copper tracks on the surfaces of the polymer sheet. Holes are drilled through the copper tracks and underlying polymer sheet to allow connection of electronic components on the top layer and/or bottom layer on the PCB. The components are therefore connected and exposed externally on the PCB.
In modern electronic circuits a great deal of the circuitry is comprised of Integrated Circuits (ICs) soldered to the PCB. This allows for a large number of active components to be mass produced into small packages that occupy little space of the PCB surface. However, a number of passive components such as inductors and capacitors cannot be manufactured in an IC package and so discrete components must be mounted separately on the PCB.
Discrete circuit components occupy greater space on the PCB and the external wiring conductors needed to connect them cause electromagnetic interference. The use of discrete circuit components also increases circuit layout complexity and thus assembly and manufacturing costs.